I have fine hair too.
I agree with massaging the scalp.
I often use a volume mousse.
Sometimes a shorter cut gives more volume.
Also dom’t compare yourself with people with thick and wavy hair
You are you and thinner fine hair can be pretty too

The very best thing is a good cut, you will need to keep it short and in good condition. My own hair is very fine and once it gets past a certain length it looks worse.

we used to do balinese wraps to promote hair growth at the salon. just massaging the scalp to promote hair growth by stimulating blood flow to the scalp..

How long is your hair. If it is long it may be stretching. The lady who lived near me had hers had hers cut into a bob, curled it at the bottom. It gave it some bulk and made it look thicker. She used a special shampoo but unfortunately I don’t know what it was.

Wow, what a problem, not sure I have an answer. I have thick and wavey hair and that annoys me!